Method of fabricating steel rule dies

ABSTRACT

A METHOD OF FABRICATING A CURVED STEEL RULE DIE HAVING A BASE MEMBER OF PREDETERMINED CURVATURE CONFORMING TO AND FOR MOUNTING ON A ROTATABLE CYLINDER WITH STEEL RULES MOUNTED IN RECESSES IN THE BASE MEMBER HAVING THEIR OUTER WORKING EDGES LYING AT A PREDETERMINED RADIUS FROM THE ROTATIONAL AXIS OF THE CYLINDER, IN WHICH THE BASE MEMBER IS INITIALLY IN A FLAT CONDITION AND WHILE IN FLAT CONDITION A PATTERN IS APPLIED AND RECESS FORMED IN THE BASE MEMBER ACCORDING TO THE PATTERN IN A MANNER SUCH THAT WHEN THE BASE MEMBER IS CURVED TO THE PREDETERMINED CURVATURE AND STEEL RULES INSERTED INTO THE RECESSES, THE WORKING EDGES OF THE STEEL RULES LIE AT THE AFOREMENTIONED PREDETERMINED RADIUS FROM THE CENTER OF TH ROTATIONAL AXIS OF THE CYLINDER.

Feb. 23, 1971 E. H. WOLFE METHOD OF FABRICATING STEEL RULE DIES FiledMay 6, 1969 Invenf0r (Zr/7W0 Zfe * aw Qi'ga United States Patent O3,564,942 METHOD OF FABRICATING STEEL RULE DIES Edgar H. Wolfe, Chicago,Ill., assignor to The Barrett Bindery Co., Chicago, Ill., a corporationof Illinois Filed May 6, 1969, Ser. No. 822,134 Int. Cl. B21k 5/20 US.Cl. 76-107 2 Claims ABSTRACT OF THE DISCLOSURE A method of fabricating acurved steel rule die having a base member of predetermined curvatureconforming to and for mounting on a rotatable cylinder with steel rulesmounted in recesses in the base member having their outer working edgeslying at a predetermined radius from the rotational axis of thecylinder, in which the base member is initially in a flat condition andwhile in fiat condition a pattern is applied and recesses formed in thebase member according to the pattern in a manner such that when the basemember is curved to the predetermined curvature and steel rules insertedinto the recesses, the working edges of the steel rules lie at theaforementioned predetermined radius from the center of the rotationalaxis of the cylinder.

BACKGROUND OF THE INVENTION 1) Field of the invention The presentinvention relates to methods of fabricating curved steel rule dies formounting on the rotatable cylinder of a press, and in which the curvedsteel rule dies embody steel rules having outer working edges lying at apredetermined radius from the axis of rotation of the cylinder toprovide desired operations such as cutting scoring, embossing and thelike on material fed through the press.

(2) Description of the prior art In my prior Pat. No. 3,322,004 datedMay 30, 1967, there is disclosed a method of making a curved steel ruledie requiring the following several steps. Initially a flat base memberfor the die is curved to correspond to the curvature of a cylinder forcarrying the die and to which a pattern for steel rules for the die isthen applied. Thereafter the curved base member is returned to a fiatcondition and suitable recesses are formed in the flat base memberconforming to the inscribed pattern on the base member. Followingformation of the recesses for the steel rules, the base member is thenagain curved to correspond to the curvature of the cylinder for carryingthe die and the steel rules are then mounted into the recesses in thebase member. According to this known method, a fiat base member must befirst curved, then flattened, and again curved in the fabrication of thedie.

SUMMARY OF THE INVENTION My present invention distinguishes from theprior art and my above referred to patent by providing a method in whichthe steps of first curving a flat base member and applying the diepattern to the curved base member are eliminated. In the presentinvention I provide a unique initial step in which the steel rule diepattern is applied with the base member in fiat condition, formingrecesses in the base member according to the applied die pattern, andthen curving the base member to the desired curvature and inserting thesteel rules into the recesses. In a curved steel rule die, the outerworking edges of the steel rules extending axially of the axis ofrotation of the cylinder on which the steel rule die is mounted aredisposed at a predetermined radius with respect to the axis of rotationof the cylinder. According to my present invention with the patternapplied to the base member in flat condition, the pattern for theaxially extending steel rules must be compensated for so that in formingthe flat recessed base member into the curvature of the cylinder forcarrying the die, the working edges of the axially extending steel ruleslie at a predetermined radius with respect to the axis of rotation ofthe cylinder. As will presently appear from the following detaileddescription of the invention, the application of the pattern to the flatbase member may be achieved in several ways.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a flatbase member for a steel rule die to which the pattern for steel ruleshas been applied;

FIG. 2 is a plan view of the base member of FIG. 1 and in which recesseshave been formed in the base member according to the pattern applied asshown in FIG. 1;

FIG. 3 shows the base member of FIG. 2 bent to a curvature to correspondto the radius of a cylinder of a press for carrying the steel rule die;

FIG. 4 is a view of the base member of FIG. 3 with steel rules insertedinto the recesses to complete the steel rule die of the invention; and

FIG. 5 is a vertical sectional view taken substantially along the line55 of FIG. 4 looking in the direction indicated by the arrows.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1 there isshown a base member 5 fabricated of any suitable relatively firmmaterial, such as plywood or plastic, characterized by being formableinto arcuate configuration, and in which recesses or slots may be formedfor receiving steel rules as will be described.

As shown in FIG. 1, a pattern is applied to the upper surface of thebase member at which recesses or slots are to be formed for receivingand supporting steel rules. In the example shown, the applied patterncomprises a plurality of pattern lines at 6 through 11, and a pluralityof pattern lines 12 through 15 extending in crossing relation to theplurality of pattern lines 6 through 11. After application of a pattern,the base member 5 as shown in FIG. 2 is recessed at lines 6 through 11,as at 6a through 11a, and at the several pattern lines 12 through 15, asat 12a through 15a to receive steel rules.

The base member 5 is then arourately curved between its end edges 16 and17, as shown in FIG. 3, to conform to the surface of a cylinder of apress for carrying the base member so that the recesses 6a through 11aextend axially of the axis of the cylinder on which the base member ismounted, and with the slots or recesses 1211 through 1511 extendingtransversely of the axis of the cylinder.

With the base member 5 in its arcuate position a plurality of straightsteel rules 6b through 11b are inserted into the recesses or slots 6athrough 11a, respectively, and a plurality of curved steel rules 12bthrough 15b are inserted into the slots 1211 through 15a, respectively.The several steel rules are supported in the base member so that theouter working edges thereof lie at a common predetermined radius withrespect to the axis of rotation of the cylinder.

In that the working edges of the steel rules are radially outwardly ofthe upper surface of the base member 5, it will be recognized that thepattern lines 6 through 11 must be applied to the base member when inits flat condition in FIG. 1 to compensate for disposition of the outerworking edges of the straight steel rules 6b through 11b to dispose suchouter working edges at the desired predetermined radius from the axis ofrotation of the cylinder. This problem, however, does not exist in theapplication of the pattern lines 12 through 15 or the slots 12a through1512 for receiving the curved steel rules 12b through 15b, in that thesecurved steel rules extend transversely to the axis of the cylinder, andsince they may be approprietely formed of curved configuration, nocompensation need be made for disposing the outer working edges of suchsteel rules at the desired predetermined radius from the axis ofrotation of the cylinder. Thus, an important facet of the invention isto apply the pattern lines '6 through 1 1 for the straight steel rulesto the upper surface of the base member 5 to provide for the desiredpredetermined positioning of the outer working edges of steel rules 6bthrough 11b inserted in the recesses of slots 6a through 11a of the basemember. This may be achieved in several ways. By way of example let itbe assumed that the bearers at the ends of the cylinder of the press forreceiving the base member 5 are of 12 inch radius, and it is desiredthat steel rules have their outer working edges lying .0125 inchradially outwardly of the outer cylindrical surfaces of the bearers ofthe cylinder of the press so that the outer working edges of thestraight steel rules 6b through 11b are at a radius of 12.0125 inchesfrom the axis of rotation of the cylinder. In this typical example thebase member 5 has its upper surface lying .1875 inch below the outerworking edges of the straight steel rules. Thus, by subtracting thedistance of .1875 inch of the base member 5 below the working edges ofthe steel rules 6b through 11b from the radius of the outer edges of thesteel rules 6b through 11b it will be found that the radius of the outersurface of the base member is 11.825 inches.

In the foregoing example, the circumference at the outer edges of thesteel rules 6b through 11b equals 75.47694 inches as derived fromdoubling the radius of 12.0125 inches times 11' (3.1416). Similarly thecircumference at the outer surface of the base member may be calculatedby doubling its radius of 11.825 inch times 11- (3.14l6) so that itmeasures 74.29884 inches. Thus the circumference of the outer surface ofthe base member of 74.29884 inches divided by the circumference of theouter working edges of the straight steel rules 6b through 11b gives afactor of correction of .98439 which, times 12 inches equals 11.81268.This is the theoretical correction per foot. Thus, in the parametersabove given, the pattern lines '6 through 11 applied to the uppersurface of the base member 5 on the basis of l11.8l268 inches for a true12 inches theoretically properly orients the pattern lines 6 through 11on the upper surface of the base member. This however, is a theoreticalcorrection per foot, but I have found that additional factors must alsobe considered. These factors are the stretch of the upper surface of thebase member when curved from flat condition, as in FIG. 1 to FIG. 2, theshrinking of the lower surface of the base member 5 when curved, and thefact that the opposite walls of the slots or recesses 6a through 11aafter formed in the fiat base member which when curved will taper towardeach other from the upper surface of the base member toward the lowersurface of the base member. Taking these and other factors into accountit was empirically determined that an additional correction of .01232inch was needed. Thus, the aforementioned theoretical correction of11.81268 inches plus the last noted additional correction of .01232 inchequals 11.825 inches. Thus a die maker in laying out the desired patternon the upper surface of the base member 5 for the pattern lines 6through 11 may utilize what may be termed a stretch ruler in which11.825 inches equals 12 inches. for the pattern lines 12 through 15 anhonest ruler may be used in which 12 inches equals 12 inches.

In FIG. 3 there is shown a so-called stretch ruler 20 and an honestruler 21 with the stretch ruler 20 being actually of 11.825 inches for12 inches, and the honest ruler 12 inches for 12. inches. In thecompleted curved steel die of FIG. 4, and as seen in FIG. 5, the outerworking edges of all the steel rules lie at the same predeterminedradius of the axis of a cylinder 25 of a press on which the diesmounted.

The use of a so-called stretch ruler and an honest ruler are convenientfor use by a die maker in building a curved steel rule die according tothe present invention.

However, the principle of application of the pattern to the uppersurface of the base member may be easily achieved by other means. Forexample, photographically or by transferred impression techniques. Inthe transferred impession technique a line drawing may be prepared usingthe above described stretch ruler and honest ruler which drawing couldthen be photographically or by transferred impression he applied to theupper surface of base member 5. The same result could be achieved byusing a line drawing or other layout that has not been corrected butinstead has been curved to the desired radius prior to photographing thesame, and then applying the photograph to the base member. Anotheralternative would be to make the pattern layout without correction andmake a photographic negative of it and then curving the negative to thepredetermined radius and projecting the negative on a positivelysensitized surface on the flat base member.

The invention claimed is:

1. The method of making a curved steel rule die from a flat base membercurved to provide a curved base member of predetermined radius having aninner cylindrical surface corresponding to the radius of the outercylindrical surface of a cylinder for carrying the die, and said curvedbase member having recesses extending axially thereof for receivingsteel rules having their outer working edges lying at a predeterminedradius with respect to the axis of said cylinder outwardly of the outersurface of said curved base member comprising the steps of formingrecesses in said fiat base member to provide said axially extendingrecesses of said curved base member, said recesses of said fiat basemember providing said axially extending recesses of said curved basemember being predeterminedly spaced apart so that upon forming said fiatbase member into said curved base member, axially extending steel rulesinserted into said axially extending recesses, will have their outerworking edges lying at said predetermined radius outwardly of the outersurface of said curved base member, curving said fiat base member to thecurvature of said predetermined radius of said curved base member, andinserting straight steel rules into said recesses of said curved basemember.

2. The method of claim 1 characterized by the further step of formingadditional recesses in said fiat base member extending transversely ofsaid first recesses to provide the recesses extending transversely ofthe axis of said curved base member, and in the last step of insertingcurved steel rules into said additional recesses extending transverselyof the axis of said curved base member with the outer working edges ofsaid curved steel rules lying at said predetermined radius outwardly ofthe outer surface of said curved base member.

12/1958 Ackley 76- 107 12/1967 Sarka 76-107 BERNARD STICKNEY, PrimaryExaminer US. Cl. X.R.

